An evil mum who drugged and murdered her two sons should have been jailed for life, the boys' father says.

Donna Fitchett, 51, yesterday was jailed for 27 years, with a minimum of 18 years, for the "chilling, callous murders" of Thomas, 11, and Matthew, 9.

"How can you not get life for taking two innocent lives, under any circumstance?" ex-husband David Fitchett pleaded to the Herald Sun.

Earlier, outside court, a grief-stricken Mr Fitchett choked back tears as he said: "My boys. I love them, I miss them." Fitchett has already served five years, meaning she could be released as early as 2023.

Prosecutors had wanted her jailed for life, which would have made her the only woman in Victoria serving a life term.

In 2008, Fitchett was sentenced to a hospital security order of 24 years, with a non-parole period of 18 years, for the murders. She successfully appealed, and faced a retrial.

"Having been through the ordeal twice, and seeking what I thought was justice for my boys after the first one (trial), going through the appeal process has been an absolute nightmare and a horrendous time in my life," Mr Fitchett said outside court.

"Thomas and Matthew deserve justice. Life by two was the only thing that would satisfy me." Fitchett drugged then strangled or smothered her boys at their Balwyn North home on September 6, 2005.

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